method
Specify the type of molecular Hamiltonian for SCF (and subsequent property) calculations.
- Input block
- Default
Short variant
method:
[hamiltonian]
/
[functional]
none
method: ks/b3lyp
method: ks-amfX2C/pbe0
method: mdks/cam-b3lyp
Note
- The explicit definition of [functional] is mandatory for Kohn–Sham-type [hamiltonian]s.
geometry
Specify the molecular geometry.
- Input block
Extended variant
geometry:
[element-symbol] [x] [y] [z]
none
#water in the xyz format
geometry:
H -0.756690 +0.466877 0.000000
H +0.756690 +0.466877 0.000000
O +0.000000 -0.119015 0.000000
#ethylene in the z-matrix format
geometry:
H
C 1 1.08
H 2 1.08 1 120.0
C 2 1.40 3 120.0 1 180.0
H 4 1.08 2 120.0 1 180.0
H 4 1.08 2 120.0 1 0.000
Note
- Angstroms are used as default units for geometry.
- The geometry can be provided either in the Cartesian (xyz) format or in the Z-matrix format.
Tip
- The default units can be changed by the keyword "geo-units".
basis
Specify atomic orbital basis sets.
- Input block
Short variant
basis:
[basis-name]
Extended variant
basis:
all : [basis-name]
[element-index] : [basis-name]
[element-symbol]: [basis-name]
none
In this example, the orbital basis "ucc-pvdz" is assigned to all elements.
basis: ucc-pvdz
In this example, the orbital basis "upc-1" is assigned first to all elements. Then, the basis is replaced by "ucc-pvdz" for the 4th element (as specified in the input block "geometry") and "dyall-vdz" for all bromine atoms.
basis:
all : upc-1
4 : ucc-pvdz
Br : dyall-vdz
Note
- In relativistic calculations the orbital basis must be in an uncontracted form. All basis sets from the internal program library are of this form.
Tip
- The complete list of available [basis-name]s can be found here.
auxbas
Specify atomic auxiliary basis sets.
- Input block
Short variant
auxbas:
[basis-name]
Extended variant
auxbas:
all : [basis-name]
[element-index] : [basis-name]
[element-symbol]: [basis-name]
none
In this example, the auxiliary basis "ucc-pvtz" is assigned to all elements.
auxbas: ucc-pvtz
In this example, the auxiliary basis "upc-1" is assigned first to all elements. Then, the basis is replaced by "ucc-pvdz" for the 4th element (as specified in the input block "geometry") and "dyall-vdz" for all bromine atoms.
auxbas:
all : upc-1
4 : ucc-pvdz
Br : dyall-vdz
Note
- The use of auxiliary basis makes sense only in connection with an approximative evaluation of electron repulsion integrals (ERI) by means of the resolution-of-identity (RI) technique. This is controled by the keyword "acceleration" in the "eri" block.
- The names of matching orbital and auxiliary basis sets are identical. Therefore, one can omit the definition of auxiliary basis, provided the orbital basis was selected from the internal program library. In this case, the program will assign the auxiliary basis automatically.
xc
Specify details associated with the evaluation of the exchange–correlation potential.
- Input block
Extended variant
xc:
hfx: [integer]
class: [string]
threshold: [real]
noncollinearity: [string]
regularization-cutoff: [real]
xc:
noncollinearity: v2005
regularization-cutoff: 1.e-30
threshold: 1.e-10
xc:
noncollinearity: v2005
regularization-cutoff: 1.0e-15
xc:
hfx: 50
Note
- In the case of open-shell systems the noncollinearity option is automatically transferred to the property calculation, therefore its repeating specification in the xc block of the respective property section is optional.
Warning
- In the case of closed-shell systems (multiplicity = 1) every noncollinearity option leads to the same noncollinear scheme for the xc potential. Therefore, when noncollinearity option is specified by the user the program will stop. The type of the noncollinearity scheme for the xc kernel of closed-shell systems may be set in the block xc of the respective property section.
eri
Specify details associated with the evaluation of electron repulsion integrals (ERI) and related two-electron Fock contributions.
grid
Specify atomic grids for the numerical evaluation of exchange-correlation DFT contributions.
- Input block
Short variant
grid:
[grid]
Extended variant
grid:
all: [string]
[element-symbol]: [string]
[element-index]: [string]
...
grid: adaptive
grid: large
grid:
C: medium
7: large
Note
- There can be multiple instances of [element-symbol] and [element-index] in the grid block.
- While lines in the grid block can be mixed, they are always processed in the following order: "all", "element-symbol", and "element-index" keywords.
- The order of processing the data matters, since the latter lines rewrite the data of the former lines. This way one can easily set the same grid for all carbons except the carbon number 7 (see example).
charge
Specify the total molecular charge.
- Input line
- Default
charge:
[integer]
charge: 0
charge: -2
multiplicity
Specify the spin multiplicity.
- Input line
- Default
multiplicity:
[integer]
multiplicity: 1 #singlet
multiplicity: 3 #triplet
convergence
Specify the convergence threshold for SCF iterations.
- Input line
- Default
convergence:
[real]
convergence: 1.0e-06
convergence: 2.5e-5
Tip
- We recommend to set the threshold value to ~1.0e-4 in cases when a loose SCF convergence is sufficient, such as in initial guess calculations, etc. For productive runs, however, the thresholds setup within the range 1.0e-5—1.0e-6 is advised. Tight convergence in the SCF is considered for thresholds below 1.0e-7.
maxiterations
Specify the maximum number of SCF iterations.
- Input line
- Default
maxiterations:
[integer]
maxiterations: 30
maxiterations: 25
nc-model
Specify the nuclear charge distribution model.
cscale
Scale the speed of light by a factor.
- Input line
- Default
cscale:
[real]
cscale: 1.0
cscale: 20.0
Note
- The scaling factor should be a positive real number. By setting cscale < 1.0, the speed of light decreases and molecular systems turn into a hyper-relativistic regime where all relativistic terms become amplified. On the other hand, by setting cscale > 1.0 the speed of light increases and molecular systems approach their non-relativistic limit.
Warning
- Due to numerical reasons, the users are advised to set the cscale parameter within the limits: 0.1 < cscale < 50.0.
1esoscale
Scale the one-electron spin-orbit interaction by a factor.
- Input line
- Default
1esoscale:
[real]
1esoscale: 1.0
1esoscale: 0.0
Note
- The scaling factor should be a positive real number. By setting 1esoscale = 0.0, one can switch off the one-electron spin-orbit interaction completely.
Warning
- Due to numerical reasons, the users are advised to set the 1esoscale parameter within the limits: 0.0 < 1esoscale < 1.0.
checkpoint
Specify the frequency of data checkpointing during SCF iterations.
- Input line
- Default
checkpoint:
[integer]
checkpoint: 10
checkpoint: 2
Tip
- The importance of more frequent checkpointing -- storing intermediate SCF data to disk for the later reuse as a restart -- increases with the system size.
spin
Control the initial orientation of spin polarization in relativistic SCF calculations.
- Input line
- Default
spin:
[string]
spin: z
spin: x
Note
- This keyword plays an important role only in relativistic Kramers-unrestricted calculations of open-shell molecules, in particular in connections with the EPR property calculations, as it controls the initial orientation of the spin polarization. In non-relativistic regime, however, the keyword does not make a sense and is therefore ignored.
[string] | description |
---|---|
eht | extended Hueckel's theory |
bare | one-electron (bare nucleus) Hamiltonian |
atomic | superposition of atomic densities |
[string] | description |
---|---|
point | point nuclear charge distribution model |
gauss | gaussian nuclear charge distribution model |
[string] | description |
---|---|
x | initial spin polarization along the x-coordinate |
y | initial spin polarization along the y-coordinate |
z | initial spin polarization along the z-coordinate |
[string] | description |
---|---|
angstrom | |
bohr |
[string] | description |
---|---|
basic | |
mulliken |
The [hamiltonian] is a string specifying the type of molecular Hamiltonian used in SCF (and subsequent property) calculations. The following options are allowed:
[hamiltonian] | description |
---|---|
ks | nonrelativistic one-component Kohn–Sham Hamiltonian |
hf | nonrelativistic one-component Hartree–Fock Hamiltonian |
ks-1eX2C | relativistic two-component Kohn–Sham Hamiltonian based on the exact two-component (X2C) transformation of the parent 4c molecular one-electron Dirac Hamiltonian |
hf-1eX2C | relativistic two-component Hartree–Fock Hamiltonian based on the exact two-component (X2C) transformation of the parent 4c molecular one-electron Dirac Hamiltonian |
ks-amfX2C | relativistic two-component Kohn–Sham Hamiltonian based on the exact two-component (X2C) transformation of the parent 4c molecular one-electron Dirac Hamiltonian corrected by superposed 4c atomic two-electron interactions |
hf-amfX2C | relativistic two-component Hartree–Fock Hamiltonian based on the exact two-component (X2C) transformation of the parent 4c molecular one-electron Dirac Hamiltonian corrected by superposed 4c atomic two-electron interactions |
ks-eamfX2C | relativistic two-component Kohn–Sham Hamiltonian based on the exact two-component (X2C) transformation of the parent 4c molecular one-electron Dirac Hamiltonian corrected by 4c molecular two-electron interactions that arise from superposed atomic density |
hf-eamfX2C | relativistic two-component Hartree–Fock Hamiltonian based on the exact two-component (X2C) transformation of the parent 4c molecular one-electron Dirac Hamiltonian corrected by 4c molecular two-electron interactions that arise from superposed atomic density |
ks-mmfX2C | relativistic two-component Kohn–Sham Hamiltonian based on the post-SCF exact two-component (X2C) transformation of the converged 4c molecular (mean-field) Hamiltonian |
hf-mmfX2C | relativistic two-component Hartree–Fock Hamiltonian based on the post-SCF exact two-component (X2C) transformation of the converged 4c molecular (mean-field) Hamiltonian |
mdks | relativistic four-component Dirac–Kohn–Sham Hamiltonian |
mdhf | relativistic four-component Dirac–Hartree–Fock Hamiltonian |
The [functional] is a string specifying the type of DFT exchange-correlation functional used in SCF (and subsequent property) calculations. The following options are allowed:
[functional] | description |
---|---|
slaterx | Slater local exchange DFT functional
J. C. Slater, Phys. Rev. 81, 385–390 (1951) |
svwn5 | Slater local exchange and Vosko–Wilk–Nusair local correlation DFT functional (LDA-type)
J. C. Slater, Phys. Rev. 81, 385–390 (1951) S. H. Vosko, L. Wilk, and M. Nusair, Can. J. Phys. 58, 1200–1211 (1980) |
bp86 | Becke non-local exchange and Perdew non-local correlation DFT functional (GGA-type)
A. D. Becke, Phys. Rev. A 38, 3098–3100 (1988) J. P. Perdew, Phys. Rev. B 33, 8822–8824 (1986) Erratum, Phys. Rev. B 34, 7406–7406 (1986) J. C. Slater, Phys. Rev. 81, 385–390 (1951) S. H. Vosko, L. Wilk, and M. Nusair, Can. J. Phys. 58, 1200–1211 (1980) |
pp86 | Perdew–Wang non-local exchange and correlation DFT functional (GGA-type)
J. P. Perdew, Phys. Rev. B 33, 8822–8824 (1986) Erratum, Phys. Rev. B 34, 7406–7406 (1986) J. P. Perdew, and Y. Wang, Phys. Rev. B 33, 8800–8802 (1986) Erratum, Phys. Rev. B 40, 3399–3399 (1989) J. C. Slater, Phys. Rev. 81, 385–390 (1951) S. H. Vosko, L. Wilk, and M. Nusair, Can. J. Phys. 58, 1200–1211 (1980) |
kt2 | Keal–Tozer non-local exchange and Vosko–Wilk–Nusair correlation DFT functional (GGA-type)
T. W. Keal, and D. J. Tozer, J. Chem. Phys. 119, 3015 (2003) J. C. Slater, Phys. Rev. 81, 385–390 (1951) S. H. Vosko, L. Wilk, and M. Nusair, Can. J. Phys. 58, 1200–1211 (1980) |
blyp | Becke non-local exchange and Lee–Yang–Parr correlation DFT functional (GGA-type)
A. D. Becke, Phys. Rev. A 38, 3098–3100 (1988) C. Lee, W. Yang, and R. G. Parr, Phys. Rev. B 37, 785–789 (1988) J. C. Slater, Phys. Rev. 81, 385–390 (1951) |
pbe | Perdew–Burke–Ernzerhof exchange and correlation DFT functional (GGA-type)
J. P. Perdew, K. Burke, and M. Ernzerhof, Phys. Rev. Lett. 77, 3865–3868 (1996) Erratum, Phys. Rev. Lett. 78, 1396–1396 (1997) J. C. Slater, Phys. Rev. 81, 385–390 (1951) |
b3lyp | Becke three-parameters exchange and Lee–Yang–Parr correlation DFT functional (hybrid-type)
A. D. Becke, Phys. Rev. A 38, 3098–3100 (1988) C. Lee, W. Yang, and R. G. Parr, Phys. Rev. B 37, 785–789 (1988) P. J. Stephens, F. J. Devlin, C. F. Chabalowski, and M. J. Frisch, J. Phys. Chem. 98, 11623–11627 (1994) J. C. Slater, Phys. Rev. 81, 385–390 (1951) S. H. Vosko, L. Wilk, and M. Nusair, Can. J. Phys. 58, 1200–1211 (1980) |
pbe0 | Perdew–Burke–Ernzerhof exchange and correlation DFT functional (hybrid-type)
J. P. Perdew, K. Burke, and M. Ernzerhof, Phys. Rev. Lett. 77, 3865–3868 (1996) Erratum, Phys. Rev. Lett. 78, 1396–1396 (1997) C. Adamo, and V. Barone, J. Chem. Phys. 110, 6158–6170 (1999) J. C. Slater, Phys. Rev. 81, 385–390 (1951) |
lc-svwn5 | Long-range corrected Slater local exchange and Vosko–Wilk–Nusair local correlation DFT functional (range-seperated LDA-type)
H. Iikura, T. Tsuneda, T. Yanai, K. Hirao, J. Chem. Phys. 115, 3540 (2001) A. Savin, in Recent Advances in Density Functional Methods, Part I , 129 (1995) J. C. Slater, Phys. Rev. 81, 385–390 (1951) S. H. Vosko, L. Wilk, and M. Nusair, Can. J. Phys. 58, 1200–1211 (1980) |
lc-blyp | Long-range corrected Becke non-local exchange and Lee–Yang–Parr correlation DFT functional (range-separated GGA-type)
H. Iikura, T. Tsuneda, T. Yanai, K. Hirao, J. Chem. Phys. 115, 3540 (2001) A. Savin, in Recent Advances in Density Functional Methods, Part I , 129 (1995) A. D. Becke, Phys. Rev. A 38, 3098–3100 (1988) C. Lee, W. Yang, and R. G. Parr, Phys. Rev. B 37, 785–789 (1988) J. C. Slater, Phys. Rev. 81, 385–390 (1951) |
cam-b3lyp | Range-separated Becke three-parameters exchange and Lee–Yang–Parr correlation DFT functional (range-separated hybrid-type)
T. Yanai, D. P. Tew, N. C. Handy, Chem. Phys. Lett. 393, 51 (2004) H. Iikura, T. Tsuneda, T. Yanai, K. Hirao, J. Chem. Phys. 115, 3540 (2001) A. Savin, in Recent Advances in Density Functional Methods, Part I , 129 (1995) A. D. Becke, Phys. Rev. A 38, 3098–3100 (1988) C. Lee, W. Yang, and R. G. Parr, Phys. Rev. B 37, 785–789 (1988) P. J. Stephens, F. J. Devlin, C. F. Chabalowski, and M. J. Frisch, J. Phys. Chem. 98, 11623–11627 (1994) J. C. Slater, Phys. Rev. 81, 385–390 (1951) S. H. Vosko, L. Wilk, and M. Nusair, Can. J. Phys. 58, 1200–1211 (1980) |
Set the noncollinear scheme for the evaluation of the exchange–correlation (xc) potential.
[string] | description |
---|---|
v2005 | The 2005 version of the noncollinear xc scheme was for the first time used in the ReSpect for the calculation of g-tensor at two- [Malkin2005] and four-component [Repisky2010] level of theory. The implementation details of the noncollinear xc energy and potential can be found in reference ReSpect article [Repisky2020] in eqs (63) and (68), respectively. This version of the noncollinear scheme was used in all ReSpect calculations until 2019 whenever spin-orbit effects have been included variationally. In particular, the noncollinear xc potential was used in evaluation of scf procedure and subsequent calculation of EPR (gt and hfcc) or paramagnetic NMR parameters (cs and sscc). The 2005 version of the noncollinear scheme is not suitable for frequency-dependent response property calculations (tddft and cpp), which is its most notable disadvantage. I. Malkin, O. L. Malkina, V. G. Malkin, and M. Kaupp, J. Chem. Phys. 123, 244103 (2005) S. Komorovsky, M. Repisky, O. L. Malkina, V. G. Malkin, I. Malkin-Ondik, and M. Kaupp, J. Chem. Phys. 128, 104101 (2008) M. Repisky, S. Komorovsky, E. Malkin, O. L. Malkina, and V. G. Malkin, Chem. Phys. Lett. 488, 94–97 (2010) M. Repisky, S. Komorovsky, M. Kadek, L. Konecny, U. Ekstrom, E. Malkin, M. Kaupp, K. Ruud, O. L. Malkina, and V. G. Malkin, J. Chem. Phys. 152, 184101 (2020) |
v2019 | The 2019 version of the noncollinear xc potential have been published in the framework of LR-TDDFT [Komorovsky2019]. This is the most general formulation of the noncollinear scheme and can be used for prediction of all spectroscopic parameters available in the ReSpect. The noncollinear xc potential is formulated in the analytic form. The implementation details of the 2019 version of the noncollinear xc energy and potential are summarized in ref [Komorovsky2019] in eq (16) and Table I, respectively. In the output files we refer to this formulation of the noncollinear xc scheme as WSK2019 ([Wullen2002] + [Scalmani2012] + [Komorovsky2019]). C. Van Wüllen, J. Comput. Chem. 23, 779–785 (2002) G. Scalmani and M. J. Frisch, J. Chem. Theory Comput. 8, 2193–2196 (2012) S. Komorovsky, P. Cherry, and M. Repisky, J. Chem. Phys. 151, 184111 (2019) |
The cutoff parameter used to regularize unstable parts of the noncollinear exchange–correlation potential and kernel (see Table I in ref [S. Komorovsky, P. Cherry, and M. Repisky, J. Chem. Phys. 151, 184111 (2019)]).
Set positive real number that specifies the screening threshold for evaluation of the exchange–correlation contribution to the Fock matrix.
Set integer number that specifies the percentage of the Hartree–Fock exchange admixture in hybrid DFT functionals.
The [string] specifies the class of overlap distribution functions (Omega) used for the evaluation of exchange-correlation Fock matrix.
[string] | description |
---|---|
llll | evaluate only the Omega(LLLL) class (default for one- and two-component Hamiltonians) |
ssss | evaluate exactly all Omega(LLLL), Omega(LLSS), Omega(SSLL), and Omega(SSSS) classes (default for four-component Hamiltonians) |
The [string] specifies the type of electron repulsion integral (ERI) classes used for the construction of the four-component two-electron Fock matrix. Note that in the four-component calculations based on the Dirac-Coulomb Hamiltonian, there are four classes of ERI, namely [LL|LL], [LL|SS], [SS|LL] and [SS|SS], where L/S refers to the large/small component type of basis. The computational complexity for evaluating those integral classes grows in the order [LL|LL] < [LL|SS] ~ [SS|LL] < [SS|SS], whereas their relative contribution to the two-electron Fock decreases in this order. Therefore, the purpose of the keyword is to neglect some of the costly ERI classes from evaluation. Note, this keyword can speed-up calculations significantly but be careful when using the most aggressive eri-cutoffs, namely the “class: ssll” option. The following options are allowed:
[string] | description |
---|---|
llll | evaluate only the [LL|LL] class (default for one- and two-component Hamiltonians) |
ssll/abcd | evaluate exactly [LL|LL], [LL|SS] and [SS|LL] classes but neglect [SS|SS] |
ssss/aabb | evaluate exactly [LL|LL], [LL|SS] and [SS|LL] classes and use an one-center approximation for [SS|SS]. In this approximation, both functions in [SS| and |SS] should share the same atomic center, otherwise they are excluded from evaluation. This is the default for four-component Hamiltonians. |
ssss/abcd | evaluate exactly all four ERI classes |
The [string] specifies the type of algebra used for the construction of the four-component two-electron Fock matrix. The following options are allowed:
[string] | description |
---|---|
c4 | complex algebra over 4Nx4N matrices |
h2 | quaternion algebra over 2Nx2N matrices |
The [real] specifies the internal threshold for evaluation of ERI.
The [string] specifies the type of approximation used for the construction of two-electron Fock matrix. The following options are allowed:
[string] | description |
---|---|
ri-j | resolution-of-identity (RI) for the two-electron Coulomb term |
none | no approximation imposed |
The [eri] is a string specifying the methodology used for the evaluation of electron repulsion integrals (ERI). The following options are allowed:
[eri] | description |
---|---|
ri-j | resolution-of-identity (RI) for the two-electron Coulomb term |
exact | exact evaluation of four-center two-electron integrals |
Specify the grid quality for all atoms in the molecule.
[string] | description |
---|---|
coarse | Adaptive angular part with a fixed radial number of points calculated as 30 + (10*p), where p is the period number of the defined element. |
medium | Adaptive angular part with a fixed radial number of points calculated as 40 + (10*p), where p is the period number of the defined element. |
large | Adaptive angular part with a fixed radial number of points calculated as 50 + (10*p), where p is the period number of the defined element. |
adaptive | Adaptive grid in both the radial and angular part calculated from the input basis. |
Specify the grid quality for atoms defined by the element symbol.
[string] | description |
---|---|
coarse | Adaptive angular part with a fixed radial number of points calculated as 30 + (10*p), where p is the period number of the defined element. |
medium | Adaptive angular part with a fixed radial number of points calculated as 40 + (10*p), where p is the period number of the defined element. |
large | Adaptive angular part with a fixed radial number of points calculated as 50 + (10*p), where p is the period number of the defined element. |
adaptive | Adaptive grid in both the radial and angular part calculated from the input basis. |
Specify the grid quality for a specific atom defined by its index in the input geometry.
[string] | description |
---|---|
coarse | Adaptive angular part with a fixed radial number of points calculated as 30 + (10*p), where p is the period number of the defined element. |
medium | Adaptive angular part with a fixed radial number of points calculated as 40 + (10*p), where p is the period number of the defined element. |
large | Adaptive angular part with a fixed radial number of points calculated as 50 + (10*p), where p is the period number of the defined element. |
adaptive | Adaptive grid in both the radial and angular part calculated from the input basis. |
Specify the grid quality for all atoms. The following options are allowed:
[string] | description |
---|---|
coarse | Adaptive angular part with a fixed radial number of points calculated as 30 + (10*p), where p is the period number of the defined element. |
medium | Adaptive angular part with a fixed radial number of points calculated as 40 + (10*p), where p is the period number of the defined element. |
large | Adaptive angular part with a fixed radial number of points calculated as 50 + (10*p), where p is the period number of the defined element. |
adaptive | Adaptive grid in both the radial and angular part calculated from the input basis. |
Latest Publications
Book chapter on relativistic real-time electron dynamics
Book chapter on relativistic theory of EPR and (p)NMR
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Department of Chemistry
UiT The Arctic University of Norway
Tromsø, NO-9037 Norway
Email: info@respectprogram.eu